Measured-service telephone system.



J. ERICKSON. MEASURED SERVlCE TELEPHONE SYSTEM. APPLICATION FlLED MAY 5. 1911.

1,257,828. Patented Feb. 26; 1918.

4 SHEETSSHEET I.

J. ERICKSON.

MEASURED SERVICETELEPHONE SYSTEM. APPLICATION FILED MAY 5. ml 1.

1,257,828. Patented Feb.26,1918.

4 SHEETSSHEET2.

Wxwvzsszs EVE/V705."

. Q 0 4 0 GWrM HTTOR/VEXs:

J ERICKSON.

MEASURED SERVICE TELEPHONE SYSTEM.

I APPLICATION FILED MAY5,|9I1. I

1,257,828. Patented Feb. 26, 1918.

4 SHEET$$HEET 3.

'IIHIIIIIIIIIIII .1. ERICKSON. MEASURED SERVICE TELEPHONE SYSTEM.

I APPLICATION FILED MAYS, 19H. 1,257,828.

Patellted Feb. 26, 1918-.

4 SHEETS--SHEET 4.

a W R m a 2. ll u WIT/V5555? v UNITED STATES PATENT OFFICE.

JOHN ERICKSON, OF CHICAGO, ILLINOIS, ASSIGNOR TO AUTOMATIC ELECTRIC COMPANY,

OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS,

MEASURED-SERVICE TELEPHONE SYSTEM.

1 '0 all whom it ma concern:

Be it known t at I, JOHN ERICKSON, a citizen of the United States of America, and resident of Chicago, Cook county, Illinois, have invented a certain new and useful Improvement in Measured-Service Telephone Systems, of which the following is a specification. Y

My invention relates to measured service telephone systems in general, but more particularly to automatic or semi-automatic telephone exchange systems, and especially to systems in which a common or central source of talking current is employed.

Generally stated, the object of my invention is to provide an improved and highly efiicient measured service' telephone exchange system.

To these and other useful ends my invention contemplates a substation service meter of such character that it cannot be operated by the calling subscriber to register the call untilafter the called subscriber has answered'.

'- tween a calling substation A (Fig. 1)

' when the meter is manually operated by the calling subscriber, whereby such operation serves both to re ister the call and place 'the calling subscri er in a position to converse with the called subscriber.

It further contemplates a substation service meter of this kind in which provision is made for preventing more than one operation thereoffor each call,

- The nature and advantages of my inven- 'tion will, however, hereinafter more fully appear.

In the accompanying drawings, Figures 1 and'2 represent a complete. connection beand a, called substation A (Fig. 2)' in a system embodying the principles of my invention.

' Specification of Letters Patent.

Patented Feb. 26, 1918.

Application filed-May 5, 1911. Serial No. 625,179.

In Fig. 1 there is represented an automatic substation A to the line conductors of which there is allotted at the central ofiice an individual or line switch C. At D there is shown a master switch for controlling a group of line switches C. The lin'e'switches of this group have common access'to a number of trunk lines which lead to first selector switches E. A number of first selec tors have common access to a number of second selectors F, which in turn have access to connector switches H (Fig. 2) by means of which connection may be completed with subscribers lines, said selectors and connectors respond to the numerical operations of the calling subscriber and for that reason aresometimes spoken of as nu mer1cal switches.

Fig. 3 is a diagrammatic view of a portion of the central office apparatus, showing the essential features of the master switch D (Fig. 1).

Fig. 4 is a front elevation of my improved call register device.

Figsi5and 6 are a side and end view, respectively, of the same.

Fig. 7 is a partial sideview taken on the side opposite that shown in Fig. 5.

As illustrated in the above drawings, the construction and method of operation of the call register is as follows: In Figs. 4:, 5 and a face plate 2 shown, to the back of which there is attached a polarized electromagnet comprising the coils 9 and 10, a permanent magnet 11 and a pivoted armature 8. Attached to the armature there is a downwardly projecting arm 12, the lower end of which is bent at right-angles and projects forward through an openin in the plate 2. On the front of the plate 2 .t ere is mounted a group of contact springs 4, 5, 6, 300 and 301. On the lower end of the spring 4 there is pivotally mounted-a flat strip 7, upon the upper side of which there is a small projection or lug 13. By means of the coiled sprin 14 the upper side of the strip 7 is cause to bear against the underside of the forward rojectlon on the arm 12. 011 the back of t e plate 2, and near the lower end thereof, there is mounted a counting mechanism-311 which ma be operated by e pawl 15 through the me iumof the ratchet wheel 16. The pawl 15 is pivotally attached to the arm 17, which is fimfl secured to the share.

an it -1 the vertical, arm of the lever 302 is attached tooth aroun to. the lower end of the spring 4. Journaled at the point 304- on the lug 19 there is a bell crank lever 305. The upper end of thevertical arm of the lever 305 is provided with a hook which registers with. the teeth of the wheel 16. To the end of the horizontal arm of lever 305 there is attached a vertical which passcsthrough an opening in thhra'fckct 307. The upper end of the arm 306' .darries a small projection 308 which normally rests slightly below the'plane of the strip 7. With the apparatus in the position shown in Figs 4-, '5, 6 and 7, it will be seen that if the button 22 is pressed it will cause the pawl. 15 to be pushed forward, and it will be pulled back again by the spring 309 when the button is released; but this operation of the pawl has no effect on the wheel 16, because it is held above the wheel by the lever 302. If, however, the magnet coils 9 and 10 are'encrgized in the proper direction to at-' tr'act'the armature 8 in a counter-clockwise direction, the lower end of the arm 12 will be'carried behind the projection 13 on the strip 7. If the magnet then be energized in the opposite direction, the arm 12 engages the projection 13, moving the strip 7 to the left and bringing the end of said stri againstthe arm 300. When the strip 7 is ullcd over it forces the springs 4, 5 and 6 into contact, separates the springs 300 and 301 and'tips the lever 302 in a counter-clock wise direction so asto allow the pawl 15 to drop down into engagement with the teeth of the wheel 16. If, now,the but-ton 22'is .pressed, the. 'a'wl 15 will be advanced one the wheel 16, and when the button is released the return movement of the' pa'wl advances the Wheel16 and counter disks of'the register bne step. As the wheel 16"rotates it {rot tes the lever 305 (Fig.5) in clt wise direction, causing the end of its horizontal arm to raise the arm 306 against the tension of the sprin 310 (Figs. {and 6). 1 As the arm 3O61is li ted the projcction 308 is carried above-the strip 7. Af-

thew .heel l6'has" completed its advance movementthehook on the upper end of the lever 305 dropis into the next notch and the springBlO-pu s the arm 306 downward. As

= arm 12. The spring 4: then returns to nore arn'i806'descends the projection 308 ,en.-' gages-the p. 7-an'd trips it off from the the wheel 16. Thus the counting mechanism can be operated again only after the current in the magnet coi s has been reversed twice, first to bring. the arm 12 behind the lug 13, and, second, to swing the strip 7 to the left and to tip the lever 302 downward. The whole mechanism, with the exception of the push button, may be inclosed in a suitable box provided with two openings in its face, one through which the push button may project, and another through which the numbers on the counting mechanism may be seen.

The general operation of the calling device in the system shown herein is as follows: When the calling subscriber initiates a call, the magnet of his register device receives current in such a direction as to attract the armature toward the coil 10. When. the called subscriber answers, after the connection is completed, the current in the calling line is reversed, .which attracts the armature of the register device in the opposite direction, operating the contact springs-and placing the counting mechanism in operativerelation to the push button. \Vhen the contact springs are in their opera-ted position, the circuits of the calling substation are placed in such a conditionthat the calling subscriber can hear the called subscriber, but cannot talk to him. In order to place the eallingsubstation in operative condition for talking, the calling subscriber must press not only restore the calling telephone to operative condition. but will also register the call on the counting device.

The automatic'substations may be of any suitable or approved type. Those in connectionwith which I have elected to illustrate my invention, as shown in Fig. 1 at A, comprise the usual receiver 25, switch hook 26, transmitter 27 ringer 29 and condenser 30. Inaddition, the substation A is provided with the impulse springs 31 and 32 and an impulse wheel 33. The impulse wheel 33 carries upon its periphery the impulse teeth 34 and is secured to a shaft 35 to which there is also attached a dial (not shown) provided with finger holes, through the medium of which the impulse wheel may be rotated. As the impulse wheel is returned to normal position by a spring (not shown) after it has been rotated for any digit, each of the teeth 34 which pass the end of the spring 31 forces said spring out ofengagement with the spring 32. The number oft imes these springs are separated depends upon the digit called. Connected tothe line of the substation A there is also shown one of my improved call-register devices. The call-register device is represented The line switch C, which is individual to the line of substation A, and the master switch D are modified formsof the general t pe of, line switch and master switch disclosed in British Patent No. 26,301 of 1906, and in the American Telcphone elournal of New York, N. Y., of June 6, 1908. As herein represented, the line switch C comprises, among other details, a plunger 38 (Fig. 3) attached to the end of a so-called plunger arm 39 which iscontrolled by the magnet 40. The magnet 40 also controls the relay I armatures 41 and 42 and is composed of four I windings, namely, a pull-in winding 43, a 16. holding or cut-ofi winding 44, a line winding 46 and an auxiliary winding 45. The

core of the magnet is provided near the center of its length with a lateral projection 47, by means of which the magnet is mounted upon the bracket 48, upon which latter the armatures 39, 41 and 42 are pivoted. With this method of mounting the magnet the magnetic circuit of the windings 43 and 44 is maintained separate from that of the windings 45 and 46, so that the armatures at one end of the. magnet are not aflected by the en'ergizationpof the windings upon the othe'fefrdfl-MOf the two windings .upon the upper end of the magnet, only the winding 43 is strong enough to attract the plunger farm 39 from its normal position. The winding not strong enough to thus operate th BQIun'ger arm, but will hold it in an M rated position'after it has been drawn own by the winding 48. Whenthe plunplunger of the switch is forced into a L ank of contact-springs, forcing springs 49, '51, 53 "and 55 into engagement with'springs 50, 52, 54 and .56, respectively. Although lygo e set of springs 49 56' is shown, "each li e .0 of sue of springs, each group form- 'ijig'jthe'l final of a trunk line leading to a selector "Each-trunk lineis multipled rough thecorresponding springs of all the line'jswitChes of the group which is conamn sty the master switch, D. The plun- .gers .o f the'line switches of this group nor- 'e' y ens? e D, are npr'mally maintained opposite the terminal 'of an idletrunk line. The master switch 1 consists; essentially of amotor magnet 58 for .66, rotating the" ratchet wheel 59. The ratchet 159 is connected with the shaft 60 ans of a link 61 in such a manner that i'. {a rotary motion of the ratchet wheel is transmittedftothe plunger-shaft 57, imparting to 565 it an oscillating i edge with a num- -eta M emm o e er" arm 39 is attracted by the magnet 40,

is provided with a number the plunger shaft 57 (Fig. 3) and;'t; hrou'g the medium of the master switch 88, and 'is control ed 89 and rotary magnet 90.

engaged by the 'pin 64 upon the end of the armature ofthe relay 66. The openings in the plate 62 are so spaced that the pin 64 I can engage one of them only when the plungers that are in looking engagement with the plunger shaft are directly in front of the corresponding trunk terminal. The master switch is alsoprovided with a bank of contacts comprising a common segment 65" and;

one individual segment a for each trunk to which the line switches have access. The wiper 66 always keeps the common segment inelectrical connection with the individual segment corresponding to the trunk line before which the idle plungers are being held by the master switch.

The selector E is of the general type of vertically and rotatably movable shaft (not shown) which is controlled by the vertical magnet 70 and rotary -magnet 71. The usual side switch, comprising the wipers 72,

'73, 74 and 75, is controlled by the private magnet 76 in a well known manner. The operation of the selector is controlled by the calling subscriber throu h the medium of. the double-wound line re ay 77. Means for restoring the mechanism of the selector to normal position is provided in the release magnet 78, which is' connected with the battery only when the switch shaft is raised one or more steps, whereby the arm 79, which is carried by said shaft, permitsthe spring 81 to engage the spring 80. The mechanism of the selector E is released immediately upon the energization of the release magnet, rather than by its denergization as shown in the said selector patent. The relays 82,

83 and 84 are slow actin rela s, 0., they are 'slowto denergizea ter t on energizing circuits have been broken. I This slow action is usually accomplished by securin 'a heavy ring of copper aroundone end 0 The-selector F is simithe coreof the rela lar to the selector with the addition of the side switch wiper 85.

The connector H is of the general ty e of connector switch disclosed in United, tates Letters Patent 815,176,'granted'March 13,

1906, as Keith,

erate in a two-wire system. Like the selectors, the connector is provided with a shaft (not shown) Ira-Pr in the wiiers 86, 87 and is the ertical magnet The usual side rickson and Erickson, but, like theselectors, is modified in order to op-- bridge relay switch is controlled by the private magnet 91 in the usual manner. The line relay 92 is connected with the line conductors 'throu h the springs of a reversing relay 93. T e connector is provided with a so-called back 177, through which the called substation is provided with talking batte current, and with a ringer relay throug the medium of which ringin current may be applied to the called line a ter connection is completed therewith.

The substation A and line switch 0 are similarto the substation A and line switch 0,. respectively. At M there 'is shown a ringing current generator and at his shown a busy signaling machine comprising a cur-' rent interrupter 93 and an induction coil 94; For operating the central ofiice apparatus and for furnishing talking current thereis provided a battery B having one p016 r (preferably the positive) grounded at Having given a general description of the apparatus, I will now explain in detail the operations 'by which one subscriber establishes connection with another in a system embodying the principles of my invention;

It will be explained how substation A may obtain connection with substation 'A', the number of which is assumed to be 2220.

When the calling subscriber removes his recei'ver preparatory to making a call, the

the Switch C.

. 10 and 9 of the call-register device, springs switch hook rises, permitting the spring 95 I I I to pass out-of en' agement with spring 97 u and into contact with spring 96, wherebyvthe circuit of the ringer 29 and condenser 30 is broken, and a bridge consisting of the sub 300 and 301, line 98, springs 104 and 103 and winding 46 to the battery lead 100. The

current through the coils of the call-register device at this time flows in such a direction asto attract the armature toward the coil 10, as shown in Fig. 1,,thereby bringin the end'of the arm 12 into engagement wit the lug 13 on the arm 7., T e energization ofthe windin 46 serves to attract the armature 42, which operates to force the spring 105 into p whereb aclrcuit is closed throug the ull-- agement' with th'e-s ring 101,

in win in '43. This circuit extends rom ground G throitllgh the springs 101 and 105,

win

windings 43 an 45, contact point 107 and armature to the battery lead 100. The

sprin 43, upon energigation, attracts the armature 41 and plunger arm 39. The

armature 41, upon being attracted, operates to disconnect the line winding 46 and ground G from the callin line. The armature 42 does not fall back immediately u on A the denergization of the winding 46, ut remains held u by current flowing in the winding 45 until the plunger arm 39 forces 108 into contact with spring 109, where y the winding 45 is short-circuited and consequently deenergizes slowly to hold the armature 42 in its operated position for an instant lon er. Before the armature 42 is restored su ciently to break the circuit of'winding 43, a circuit is closed through the winding 44 in the followin manner: When the springs 49 and55 are orced into contact with springs 50 and '56, respectively,

by the plunger of the line switch C, a circuit is closed through the line relay 77 of the selector E. Th1s circuit extends from round G through lower winding of relay 7, side switch wiper 73, springs 56 and 55,

thence over the heavy conductors to and-t through substation A and back over the other side of the line through upper windin of relay 77 to the battery lead 100. The re ay 77 upon energizing, operates to close a circuit through the relay 82, saidccircuit extending from ground Gr through the springs 110 and'lll and relay 82 to battery lead 100, The relay 82, upon energizing,

operates to close the circuit of the holding winding 44 of the lineswitch C, said circuit extending from 113 and 114, 52 and 51 and winding 44 to the battery lead 100. The current in this windingserves to hold the plunger arm 39 and armature41 in their operated positions after-the winding 43 has been dee'nergized. The energization of the relay 82 at the selector E also extends a guarding potential from ground G over conductor 115 to the connector private bank contacts of the ca'llin line. I

en the SEI'HlgS 53 and 54 are forced into contact y switch relay 116. This circuit extends from ground Gd? through springs 59 and 54, con: tact point 117, wiper 66, segment 65,and relay. 116 to battery lead 100. 'The relay-116, upon energizin operates to close a circuit through the re ay 66. The felay 66, upon from the plate 62 and to close the circuit of the motor magnet 58. This circuit extends from ground G through mag'net 58,li nterrupter springs 118, contact ,pint,]19 and armature 65 to the battery lead 100. As long as the armature 65 engages the contact point 119, the magnet 58 operates in a manner similar to that )of' a-buzzer to rotate'the ratchet wheel 59=stepby step. to advance the li'd'le line switch lungerseaway from the trunk jus'tseized. Xfter the-plunound Gth-rough springs the plunger of the line switch, a circuit is closed through the master energ1zing, operates to withdpaw the pin energize.

1 plate 62 passes under the pin 64. When the next opening does pass under'the pin 64 the armature 65 falls back, forcing the pin into this opening to-lock the plunger shaft, and

breaking the circuit of the motor magnet 58.

and. any subscriber who attempts to make I a ,call at that time will receive the busy sig- The foregoing is the operation of the master switch in case the next trunk line after the one seized by the switch C is idle. If, how

ever, this next trunk is busy, the wiper 66 finds the corresponding contact in the mas-- ter switch bank grounded, and cons uentl the relays 116 and 66 remain ener ize while the next opening is passing un er the pin '64 and the plungers are carried past the busy trunk to an idle one. Aslong as the master switch-is operating, the armature is disengaged from the spring 107 and sgring 107 'engagesthe s ring 120, whereby t e pull-in windings 0 all the idle line switches are disconnected-from the battery and connected to the busy signaling machine L. With this arrangementn'o line switch can be operated wh le its plunger is being moved from one trunk to another,

nal, due to the inductive relation between the line winding 46 and which is then connected to the busy signal- I mg machine L.

The foregoing are the operations which take place immediately upon the, removal of the receiver at the calling pulse. wheel 33'returns to nor after being rotated for this digit, the impulse springs 31 and 32 are separated twice momentarily. I Each time the springs 31 and 32-are separated, the energizlng circuit of allowing said relay to be momentarily deenergized. Since the relay 82 of the selector is slow acting, it does not have time to deenergize during the momentary interruption uof its circuit at 'the springs 111 and 110.

Consequently, the

110 and 112 closes through the vertical magnet 70. cuit extends from ground G through springs 110 and 112, springs 121 and 122, private maignet relay 83, vertical ma net and the si e switch wi er 74 to the attery lead 100. Since the digit'called is 2, the vertical magnet receives .two impulses over this circuit and operates to raise the switch shaft and wipers two steps'to a position op engagement of springs an energizing circuit the winding 45,

a1 position his cir- 'posite the second row or level of bank contacts. The private magnet relay 83, which is included in the energizin circuitof the vertical magnet, is energiz with the first and llows the side switch to pass to second connects the battery from the vertical ma net 70 and completes an energizing circuit throu h the rotary ma et 71. This circuit extends from ground 2 through the inter rupter springs 120, rotary magnet '71, relay 84 and side switch 74 tobattery lead 100. Upon the closure of this circuit the rotary magnet attracts its armature, which operates to rotate the shaft wipers one step, to press down the armature f the private magnet 76 and toopen the circuit of its own magnet at the interrupter springs 120.- When the circuit of the rotary magnet is .thus opened, its armature falls back and,

if the first trunk line upon which the wipers have jnst been rotated is not already in use,

the private magnet armature also falls 'back and permits the side switch to pass to third position. If, however, the first trunk line of the'second level is already busy, the priv ate wiper 68 finds the first contact which 1t engages provided with a guarding ground potential. When the .wiper 68 thus' engages the grounded contact, the locking circuit is completed through the side 'swltch wiper 75 (in second position) and the grivate magnet '76 tobattery lead 100. he' rivate magnet thus becomes energized an locks the side swltch in second position. As ldn s the side switch remains thus locked, the

rotary magnet continues to' operate ina manner'slmllar to that of a buzzer to rotate the selector wipers step by step untilan idle trunk line is found. hen th of an idle trunk, the private magnet 7 deenergizes and permits the side switc to pass to third position, thereby breaking thecircuit of the rotary magnet. The movement of the side switch wipers 72 and 73 from second-to third position disconnectsrelay 77 of the selector E was energized 130 e private wiper 68 engages the non-grounded contact when the connection was first extended throu h that selector. The energization of the re ay 127 serves to close an energizing circuit through the slow acting relay 128 in the same manner in which the circuit of relay 82 was closed by the relay 77. The

relay 128, 1 upon energizing, extends the guarding potential from ground G7 to side switch wiper 85 and springs 129 and 130 and to the private bank contacts of the seized trunk inthe banks of all of the selectors E which have access to this trunk. A circuit alsoextends from the ound G through the said selector private ank con tacts,'private, wiper 68, side switch wiper 75, s rmgs 131 and 132 and relay 82 to battery 'ead 100. This circuit prevents the re- -1gy 82*from denergizing after its former ank contacts from the ,this-intervalthetrunk ineleading to the J 'rela circuit is broken b the deenergization of the role ;77 when t e side switch of the selector to third position. A short period 0 time elapses between the time ,WhBII'ithH side switch or the" selector E F3 9 is d r s t b and thetime when e relay 128ei1'er'gizes to extend a guarding potential back to the firstselec'tor private ound G. During selector F is guarded by a ound potential extending from ground 5: through the springs 133 and 131, ide switch wiper v75 andprivat'e, wiper 68. to the private bank contacts. It will be remembered that the 84 is included in the operating circuit of t e rotary magnet 71 and, since it is a slow acting relay an instant after the rota magnet is energized for the last time. bus the relay 84 1s alread energized when the side switch reaches t'ird position, and a guarding potentialis extended from ground Gr in the 'mannerdescribed. The relay 84 is quicker, than; thevrelay 82 and thus deenergmes in time to close the new energizing circuit for the relay 8 2 before it has time to deenergizfe.

The calling subscribernow operateshis cellin device forthe second diget 2. The secon selector F k V (aperates in response to the impulses for this i as'explalned for the selector- E,'and extends connection toan idle connector-H over the trunk lines 184 and 135. When the connection is thus extended to the connector H its theslow acting relay 139 Jrgizing, extends the. guarding ote'ntial fro groundG" throng};

" line relay 92 becomes. energized in the same manner that the selector lme relays are energized, The relay 92, upon ener 'zing, op-

erates to complete a circuit exten ing'from ground G" through springs 137 and 138' and to battery lead 100, The relay 139, upon on side switc wiper 1 springs 141 and 1 and conductor 186 to allot the selector pri to bank con ts which belon to the tru 'line leadin to the connector The it remains energized for E'to close'the circuit of the private Ina g1t in the same manner 146,147 and 148,-relay 149, springs switch'wiper 144 and springs 145 and 145' ,to point 147.

From point 147 one branch ofthis circuit extends throu' h the relay 128 if to battery, while another ranch extends through the side switch wiper 85 (in third position) to and through the relay 82 of selector Efover a circuit which has already been traced. I

Thecallin subscriber now operates his dial for the t ird digit 2, momentarily separating the impulse sprin 31 and 32 in the same manner as describe for the first digit.- Each time the impulse springs are separated 86 for the third digit, the energizing circuit for the connector line rela 92 is. broken mornentarily-i Since. the re ay. 139 oftlie connector is slow acting it does not have time to deenergize during the momentary denergization of the relay 92; consequently the engagement of springs 137 and 146 com pletes an energizing circuit through the vertical ma net 89, r This circuit extends from ground 5 through the springs 137 and 146,

springs 147 and 148, prlvate magnet rela 149, vertical magnet 89 and side switc cuit and operates to raise the shaft wi ers 86,. 87 and 88 two steps, The private-mag net relay 149 operates in the same manner as V the private ma et relay 83 of thcselector et while the vertical magnet is operating. he 105. circuit through the private magnet extends, from ground Gr through springs 15.1 and 152 and private ma net 91 to battery lead 100; This circuit is roken shortly after the last impulse is delivered to thevertical m agnet, whereupon the private magnet deinergizesand permits the side switch to ass to "third position. The movement of t e side switch wiper 150 rom first to second position transfers the; battery connection from the yertical magnet 89 to the rotary magnet The connector is then in posltlon to receive impulses for the last di t 0. The operation of thevsubst'ation caling device for this digit breaks the energizing circuit of the relay 92 temtimes. Each timethe relay 92 dee'ne'rgizes it completes a circuit extend ing from ground G through springs187,

15s and 154,1-otary,magnet 90 andcside swltch wipe11; ;}.26

in second position) to the battery lead 100 The rotary magnet 90 receives teatimp this circuit and operatestorbtate' t ten stepsonto the contacts of line 7 The private magnet relay149,3

' When the side switch circuit is establishe the first impulse to the rotary magnet an again closes the circuit of the private magnet 91. The circuit ofthe relay 149 is not opened long enough to permit it to denergize until after the last impulse has been delivered to the rotary Ina et The relay 149 then'denergizes and ii daks the circuit of theprivate magnet 91 which, if the called line is not already busy, in turn deenergizes and permits the side switch to pass to third position, whereby connection is completed between the calling and called lines. The side switch wiper 156 (in third osition) extends the uarding potential roni ground Gr throng]? the private wiper 87 to t e connector private bank contacts of energized 121v the called line, and also provides enerthe cutoff winding 157 of gizing circuit for the line switch 0. The winding 157, upon energizing, attracts the armature 158, which operates to disconnect the line winding 159 and ground G from the called line, and to extend the line conductor 160 through the springs 162 and 163 to the connector bank contact which is engaged by wiper 86.

wiper 150 of the connector reaches third osition, the energizing d for the ringer relay 164, This circuit extends'from ground Cr through the interrupter 165, relay 164, springs 171 and 170 and side switch wiper 1.50 to the battery lead 100. Since this circuit includes the interrupter 165, the relay 1-64 is energized only intermittently. Each time the relay 164 is energized it operates to disconnect the callin line from the called line, and to bridge t e generator M across the called line to ring the bell 175. When the called subscriber removes his receiver, or as soon thereafter as the relay 164 denergizes, if it happens tobe energized at the time, the called substation is provided with talking battery current from the central oflice. The circuit over which this talking current flows extends from ground G to the side switch wiper 156, 1ower winding .of

the relay 177, ringer relay springs 188 and 189, side switch wiper 187, shaft wiper 88, line 161, hook switch springs 186 and 185, receiver 184, transmitter 183, impulse springs vice, line 160, springs 162 and 163, shaft wiper 86, ringer relay springs 281 and 280,

182, coils 181 and 180 of the call-register deprivate magnet springs 179 and 17 8, upper winding of the back-bridge relay 177 andside switch wiper 150 to the battery lead 100. The current through the (Oils-1811\nd. 180 and the call-register device of the substation A in such direction atthistime as to attract the-armature toward the coil .181. When the connector back-bridge relay 177 is energized by thectalking current, it operates ,to close the circuit through the relay 93. This circuit extends from ground (1' through the side switch wiper 156, relay talking the re ease relays 139,128 an ack-bridge relay 177. Consequently, the

relay 93 will not deenergize and close the circuit of the ringer relay 164 again in case the called subscriber should hang u his receiver and break the circuit of the backbridge relay 177 before the calling subscriber has hung up his receiver. When the relay 93 is energized it also operates to shift the springs 167 and 173 out of engagement with the springs 168 and 174 and into contact with the springs 1'66 and 172, respectively. By this operation the connect ons between the windings of the relay 92 and the trunk conductors 134 and 135 are interchanged. By this shifting of the connections of the relay 92 the current in the calling line is reversed. This reversal of the current causes the polarized relay of the call-register device at substation A to attract its armature in the opposite direction-that is, toward the coil 9. When the armatureis attracted in this direction it carries th m 7 to the left, forcing the springs 4, 5 and .6

into engagement, as was explained in connection with Figs. 4 and 5. The engagement of these springs 4, 5 and 6 short-circ'uits the transmitter 27 and shunts the receiver 25 with the resistance 190. The shortcircuitin of the transmitter '27 makes it i'm- When the calling subscriber hears the called subscriber answer,

, he presses the button 22.- .This operates the anism and permits the springs .4, 5 and 6 to se arate in the manner previously explained. The separation of these springs restores the circuit (if the calling substation to operative condition, and the two subscribers may converse over the circuits outlined by heav conductors in the drawings.

Af t er the conversation-is completed, the release of the central ofiice apparatus is in-. itiated by the hanging up of the receiver at the calling substation. When the receiver 25 is restored to the switch hook 26, the springs 95 and 96 are separated, thereby breaking the energizing circuit through the connector line rela 92. The relay 92, upon deener izing, brea s the holdin circuits of 82 of the switches H, F and E, respectively. 'Al

though it has not been previously mentioned,

counter-mechtacts of the said busy line.

it will be seen that when the side switch wiper 140 of the connector passes from second to third position, the holding ground of the release relays 128 and 82 of the selector switches is transferred from ground G to ground G through the springs 138 and 137, so that the circuits of all of the release relays are controlled by the connector line relay. When the relay 139 of the connector deenergizes it completes a circuit from ground G through springs 1.37 and 146, springs 147 vand 191, release magnet 192 andofl-normal springs 193 and 194 to battery lead 100. The energization of the magnet 192 immediately restores the mechanism of the connector to normal position, thereby breaking the con nection at the called line and allowing the winding 157 of the switch C to deenergize. The de'nergization of'the release relays 128 and 82 of the selectors E and F closes the circuits of their respective release magnets. The energizing circuit fior the release magnet 78 of the selector E ektends from ground G through springs. 110 ,3115, 112, springs 121 and 123, magnet l'fijndiofimormall springs and 81 to battery 100. The "circuit of the release magnet ltgli of the selector F is similar tothat just traced for the magnet 78.

The energization ofithe magnets 78 and 193' restores the mechanism oLthein'respective; switches to normal. positiontie whentheshafts of theswitches E, FandH-reach 1 their lowest positions, the energizing circuits of their respective release jets are broken by the separation of the o -ingirmal j srings. The deenergization of 'j release r lay 82 of the selector E falsgf' lisens the holding circuit of the winding 44 in the line switch C, whereupon its plun' er returns to normal position and all of t e apparatus employed in the connection is left 1n readiness for another call.

The foregoing is an explanation of the manner in which connectionis obtained with an idle line. It will now be ex lained how the calling subscriber is given t e busy signal in case the called line is alread 1n use when called by the subscriber at su station A. In the foregoing description it has been.

explained how, whenever a line is busy, cit or by having made a call or by having been'called, there is a guarding ground potential on the connector private bank con- Thus if the wipers of the connector Hare rotated onto the contacts of the busy line, aground potential is extended from the private bank contact in that line through the private wiper 87, side switch wiper 156 (which is then in second position), springs 195 andv 196, relay 197 and; to the spring 198 of the rivate magnet relay 149. As the relay 149 deenergizes after last impulse has been delivered to the rotary magnet of the consubscriber is thus receiving the busy signa .is answered.

It will be seen thatwhen the magnet]. the 'call register is operated by the reverse; of current in the calling line upon the nector the spring 152 engages the spring 198 be fore it breaks contact with the spring 151. The circuit of the private magnet 91 is and 141, and the side switch wiper 140. In

its energized position the relay 197 also completes a circuit over which busy signal ing current flows from the busy signaling machine. L to the calling substation. This circuit extends from the battery lead through the secondary windin of the induction coil 94, springs 199 an 200, contact ay springs 188 and 189, condenser 202,

point 201, side switch wiper 187, ringer rethence over, the heavy conductors shown in :7

Figs. 2 and 1 to and through the substation A and back over the other side of the line to the upper winding of the connector line relay 92 to *battery lead 100. Although the wipers; of the connector H are standing 'on thecontacts of the called line while a callin there is no connection between the two lines.

'The connection is opened on one side ofthe line at the private magnet springs 17 8 and 179 and on the other s de at the side switch wiper 187, which is locked in second posi-' tion. The switches are released-in this position by the hanging up of the receiver at the calling substation in practically the same -manner as when anidle line is called. It will he noted that when a'busy line is called the current inthe, calling line is not reversed.

Therefore, the armature of the coin-colleet-' ing device at substation A isnot attracted] toward the coil .9 to' clos'e the springs 4,5;,;p.

and 6, but remainsjnthe position shown Fig. 1 until atsoine' subsequent time an line is called from substation thecall i replace the resistance of the'transmitten j which is short-circuited. The insertion" this resistance .is useful only d vice is used in party-lines, and

in case a second, su 'riber on a callmgi linef should remove his receiver while gigglysation is in progress. The magnet at this second telephone would energize in the direction to short circuit the transmitter, and at the same time the insertion of the impedance 315 prevents sutlicient talking current from being shunted from the first telephone to interfere with the conversation.

From the foregoing it will be seen that the calling subscribers telephone set is inoperative for talking after the called subscriber answers. The calling subscriber can listen and hear the response/of the called subscriber, but cannot use his transmitter until the call has been registered at the calling substation. This is the only way in which the calling subscriber can talk to the called subscriber. g

A further advantage of my improved system is as follows: In telephone systems giving socalled measured service it is very often desired that no charge shall be levied for-calling certain lines, such as lines which. terminate at the central ofiice over which operators or exchange attendants are called, etc. In the system shown herein it is very easy to provide for free service when certain lines are called. This may be done by making the lines whichare to be called free of charge accessible from special connector switches. These special connectors may be similar in all respects to the connector H, with the exception that the line relay 92 should be connected with the trunk conductors 134C and 135' direct instead of through the springs of the relay 93. In

these special connectors the 'relay corresponding to the relay 93 would have no springs corresponding to the springs 166, 167, 168, 172, 173 and 174. Since the line relay of these connectors is connected di rectly to the line conductors, the current is not reversed in the calling line upon the removal of the receiver at a substation which has been called through one of the special connectors. Since the current in the calling line is not reversed, the calling telephone is not made inoperative for talking, and consequently the calling subscriber does not need to operate his meter before he can talk.

My improved substation service meter is especially adapted for use intwo-wire systems. By a two-Wire system I mean one in which means are provided at the substation for controlling the two, sides of a calling line in series to operate one or more automatic switches in extending the call. This meter, as explaincd,is operable by the calling subscriber after, but not before, the called subscriber answers. It cannot be operated more than once fo'reach call, and the calling subscriber must operate the meter and thereby register the call in order to restore the transmitter to operative condition. For the broader purposes of my invention I do not, however, limit myself to the exact construction and circuit arrangement shown and described.

What I claim as my invention is 2-- 1. In a telephone system, a calling and 11 called line, switching apparatus for establishing a connection between said lines, a meter and an operating magnet at the substation of the calling line, and means controlled by said magnet for rendering the calling telephone inoperative only as to its transmitter upon the response of the called subscriber.

2. In a telephone system, a calling and 3. called subscrib'ers line, a meter and an operating magnet on the calling line, and means controlled by said magnet upon the response of the called subscriber for rendering the calling telephone inoperative for transmitting but not for receiving voice currents.

3. In a telephone system, a calling and a called line, switching apparatus for establishing a connection between said lines, a meter and an operating magnet at the substation of the calling line, means controlled by said magnet for rendering only the transmitter of the calling telephone inoperative for talking purposes upon the response of the called subscriber, and means for preventing said meter from being operated until after the response of the called sub-' scriber.

4. In a telephone system, a calling and a called subscribers line, a meter and an operating magnet. on the calling line, means controlled by said magnet upon the response of the called subscriber for rendering the calling'telephone inoperative for transmitting but not for receiving voice-currents, and means for" preventing said meter from being operated until after the response of the called subscriber.

5. In a telephone system, a calling and a called line, means including automatic progressively moved switching apparatus for establishing a connection between said lines,

crating magnet therefor, means controlled by said magnet for rendering only the transmitter of the calling telephone inoperative for talking purposes upon the response of the called subscriber, and manual means to again render said telephone operative for talking purposes and for operating said meter.

7. In a telephone system, a calling and a called line, switching apparatus for establishing a, connection between said lines, a meter for the calling line, a magnet associated therewith, means for closing an energizing circuit for said operating magnet upon the response of lll'lQ'CflllBd subscriber,

contact springs controlled by said, magnet adapted to be brought into contact upon the operation of the same, a short-circuit about the transmitter of the calling telephone, and p a shuntcircuit about the receiver controlled by said contactfsprings, whereby the calling telephone is rendered inoperative for transmitting but not for receiving voice-currents.

8. In a telephone system, aballing and 0. called line, switching apparatus for establishing a connection between said lines, a

meter for the calling line, a magnet associated therewith means for closing an energizing circuit or said operating magnet upon the responseof the called subscriber, contact springs controlled by said magnet adapted to be brought into contact upon the operation of the same, a short-circuit about the transmitter of the calling telephone. a shunt circuit about the receiver controlled by said contact springs, whereby the calling telephone is rendered inoperative for transmittingbut not for receiving voice-currents, and means for preventing said meter from being operated to register a call until after the response of the called subscriber.

- called line,

. ting current in onedirection through said,

9, In a telephone system, a calling and a called line, switching apparatus for estab- .lishing a connection between said lines, .a 40

meter for the calling line, a polarized operating magnet associated therewith, 'a circuit for transmitting current in one direction through said operating magnet when the calling subscriber initiates a call, means for reversing the current through said magnet upon the response ofthe called subscriber, and means controlled by said reversal of current for rendering only the transmitter of the calling telephone inoperative for talka ing purposes.

10. In a telephone system, a calling and a means includin switchin apparatus for establishing a connecti-on etween said lines, ameter for-the calling line, a polarized operating magnet associated therewith, means for transmitmagnet when a subscriber initiates a call, means for reversing the current through said magnet upon the response of the called subscriber, and a short'circuit about the calling transmitter adapted to be closed upon.

the operation of said ma et upon the respouse of the called subscriber to render said n meter at the; su automatic selected group for establishing a connec on transmitter inoperative, for talking par- 4 poses.

11. In atelephone system,,a-calling and a called line, switching apparatus for establishin g a connection between said lines, a meter at the substation of the calling line, a polarized electromagnet associated with said meter, an arm controlled by the armature of said electromagnet, means for closing the circuit in one direction through said electromagnet when-the subscriber initiates'a call, means for reversing the current throu h said ele'ctromagnet upon the response of e called subscriber, means formo'vlng said arm in response to said reversal of current, and contact springs controlled by 'saidarmior rendering only the transmitter at the, calling substation inoperative for talking urposes 12. In-a telephone system, a on ling and a called line, switching apparatus for establishing a connection between said lines, means for controlling'the two sides of the calling line in series for controlling the opphone inoperative for talk ng purposes upon the response of the called subscriber, and manual means for then operatin said meter to register the call and to ren er" the telephone againoperative for talking.

14. In a telephone'system, a callin and a called subscribers line,means including, automatic switches having motion in one plane to select groups and motion in a no plane at right-angles thereto. to find a line m the selected grou for establishing a connection between sai lines, a'switch hook for controlling thel'o ration of said'apparatus,

liztation of the call ng line, means included in the line circuit for op- 'erating other means for placin said meter in condition to register success ul ca lls, and manual means for operating said meterqi 15. In a tele hone system, a calling called subscri automatic switches; having motion in a ne plane to select groups and motion in :1 pl ne at right-angles thereto to find a line. in the between said men, a meter at the substa, ion of the calling line, menns-contyelled by id meter for rendering the calhng teleplt ne.

rs line, means includ g inoperative fortalking purposes upon the 16. In a telephone system, a calling and a called line, means including automatie progressively movable switching apparatus for establishing a connection between said" lines, a meter associated with the calling line, an operating magnet associated with said meter, means controlled by said magnet for rendering the calling telephone inoperative. for talking purposes upon the response of the called subscriber, and manual means for operating said meter to again render said telephone operative for talking purposes.

17. In a telephone system a calling and 9. called line, means including automatic switching apparatus for establishing a con nection between said lines, a meter associated with the calling line, a polarized operating magnet associated with said meteig'a circuit for transmitting current in one direction through said operating mdgnet when the calling subscriber initiates a; call, means for reversing the current through said magnet upon the response of the called subscriber, and means controlled by said reversal of current for rendering the calling telephone inoperative for talking purposes.

18. In a telephone system, a calling and a called line, means including automatic switching apparatus for establishin a connection between said lines, means $01 controlling the two sides of the calling line in series for controlling the operation of said switching apparatus, and a manually operated meter associated with the calling line for registering only successful-calls, said meter being contr'olledby means operated over the established connection.

19. In a telephone system, a calling and a called line, progressively movable switching apparatus for establishing a connection between said lines, a switch hook for controlling the operation of said apparatus, a meter associated with an el'ectromagnet winding in the line circuit of the calling '2 line, manual means for operatingsaid meter to register-a call, and means controlled by said Winding for preventing said meter from being operated until after the response of the called subscriber.

20. In a telephone system, a calling and a called line, progressively movable switching apparatus for establishin a connection between said lines, a normal yinoperative meter associated wlth a polarized o crating magnet in the line circuit of the calllng'line, means for transmitting current in one direction through said magnet when a subscriber initiates a call, means for reversing the current through said magnet upon the response for establishing a connection .means for operatin of the called subscriber to render said meter operative, and a short-circuit about the calling transmitter adapted to be closed upon the operation of said magnet upon the response of the called subscriber to render said transmitter inoperative for talking purposes.

21. In a telephone system, a calling and a called subscribers line, means including progressively movable switching mechanism etween said lines, a switch hook for controlling the operation of said switch mechanism, a meter associated with ,the'calling line, mechanical said meter, said meter normally inoperab e by said mechanical means, and an operating magnet for render-' ing said meter operable.

22. In a telephone system, a calling and a called subscribers line, means including progressively movable switchin mechanism for' fe's'tabli'shing a connection etween said lines, a {switch hook for controlling the operationfof said switch mechanism, a meter associated with the calling line, mechanical means for operating said meter, said meter normally inoperable by said mechanical means,an operating magnet for .controlling-jinejans for rendering said meter operableLf 23. Ina tele hone system, a calling and it called subscri ers. line means including progressively movable switching mechanism for, establishing a connection between said lines, a switch hook tor controlling the operation of said switch mechanism, a meter associated with the calling line, mechanical means for operatin said meter, saidmeter normally inoperab e by said mechanical means, an operating ma net for rendering said meter operable, an means under-the control of the calling subscriber for operating said meter.

24. In a telephone system, a calling and a called subscribers line, means including progressively movable switching mechanism for establishing a connection between said lines, a switch hook for controlling the operation of said mechanism, a meter associated with the calling line, a pawl for operatin said meter, said pawl normally disassociate from the operating parts of said meter, a magnet for associating the pawl with said operating parts, and manual means for operatin said pawl.

25. n a telephone system, a calling and a called subscribers line, means including progressively movable switching mechanism v for establishing'a connection between said lines, a switch hook for controlling the operation of said mechanism, a meter associated withthe calling line a pawl for operating said meter, said pawl normally disassociated from the operating parts 0 said meter, a magnet for associatingthe pawl with i said operating parts, and means controlled by the calling subscriber for controlling said pawl to operate said meter.

26.; In a tele hone system, a calling and a called subscriiiers line, means including progressively 'movable switching mechanism for establishing a connection between said lines, a switch hook for controlling the operation of said mechanism, a meter associated with the calling line, a pawl for operating said meter, said pawl normally disassociated from the operating parts of said meter, a magnet for associating the pawl with said operating parts, manual means for controlling said pawl to operate said meter and means for again disassociating said pawl.

27.. In a telephone system, a calling and a said release means, said magnet responsive to the talking current for operating said release means for rendering said metero'perable, and manual means for operating said meter.

28. In a telephone system, a calling and a called subscribers line, means including progressively movable switching mechanism for establishing a connection between said lines, a switch hook for controlling the operation of said mechanism, ameter associated with the calling line, a latch for nor mally preventing the meter from operating, release means for rendering said meter operable, a central battery for applying currentfor operating and talking purposes, a-

magnet responsive to the operatin current for setting said release means, sai magnet responsive to the talking current for operating said release means for rendering said meter operable, and means under the control of the calling subscriber for operating said meter.

Signed by me at Chicago, Cook county, Illinois, this'27th day of April, 1911.

JOHN ERICKSON.

\Vitnesses:

ARTHUR J. RAY, E. D. FALES. 

